Hydraulically controlled vibrohammer



Sept. 22, 1970 E G. BERRIE HYDRAULICALLY CONTROLLED VIBRO-HAMMER Filed Jan. 2, 1969 Sheets-Sheet 2 //v vex wk.-

Elf/5 654/9655 8638/6- Arm United States Patent Office Patented Sept. 22, 1970 34,7 Int. Cl. E02d 7/02,- E21b 1/02 U.S. Cl. 173-116 14 Claims ABSTRACT OF THE DISCLOSURE Vibro-hammer comprising a hollow weight serving as an inertia mass and a ram serving as a striking mass, the ram being reciprocated within the hollow weight by fluid pressure applied interiorly of two axial cylindrical mem bers or cylinders at the ends of the ram and engaging two opposed pistons secured to respective ends of the hollow weight. The weight and ram drive various working tools through an auxiliary terminal element preferably including coupling means enabling a selected degree of elasticity between the ram and the tool so the tool can be driven either by percussion or in a vibratory condition at controlled intensity. The selected tool can be driven in rotation as well as longitudinally, if desired, as When the apparatus is for drilling boreholes.

The present invention relates to an apparatus known as a Vibrmhammer, which finds its use in the drilling of boreholes, driving piles and sheet-piling, or any other operations which require that a tool should be given movements of percussion or vibration, most frequently combined with a rotary movement favourable to the effectiveness of the work of the said tool.

This apparatus essentially comprises a heavy weight or ram which it is necessary to displace with a reciproeating movement of translation inside a hollow Weight, under the action of a fluid, means for injecting a fluid for the purpose of imparting the reciprocating movement to the ram, means for fixing the tool, elastic means being interposed at will between the tool and the ram, said apparatus being characterized in that the fluid pressure is applied to the interior of two axial cylindrical chambers or cylinders formed at the two extremities of the ram, inside which are engaged two fixed pistons secured facing each other to the two ends of the hollow weight.

The above-mentioned hollow weight and the ram play respectively the parts of an inertia mass and a striking mass, to the effects of which is subjected an auxiliary terminal element which carries the various working tools.

According to a preferred form of embodiment, the apparatus further comprises means for driving the tool in rotation, this characteristic feature being especially desirable when the apparatus is intended for drilling boreholes.

In a preferred form of construction, the proposed apparatus is actuated by a hydraulic motor driving a doublepiston pump which delivers oil under pressure alternately into one and then the other of two axial cylindrical chambers bored at the two opposite extremities of the ram, and into which pass two fixed pistons secured facing each other to the two opposite ends of the external hollow weight.

The said apparatus is further characterized by the particular features recited below:

The terminal element to which the tool is fixed is coupled to the external hollow weight by an elastic device provided with an adjusting system enabling the degree of elasticity of this device to be varied so that the said tool can work, depending on the various cases, either by percussion or in a vibratory condition at controlled intensity.

The oil circulation system which forms part of the equipment of the apparatus is established in such manner that, for the purpose of precluding abnormal heating of the said oil, a constant renewal of the oil is ensured inside the cylinders of the piston pump of the hydraulic device which actuates the ram.

The terminal element to which the tool is fixed is provided with a planetary gear-box having a step-up gear ratio, the axial output pinion of Which carries a mandrel with an automatic clamping action, adapted to receive a central drilling device capable of working in the core of a tubular member directly fixed to the said terminal element.

The advantages and characteristic features of the present invention are further brought out in the description which follows below of one form of construction of the new apparatus which forms its object, described below by way of example and not in any limitative sense, reference being made to the accompanying drawings, in which:

FIG. 1 is a view in axial section of the vibro-hammer incorporating the present invention;

FIG. 2 is a diagram which shows the structure of the circuit ensuring renewal of the oil.

In FIG. 1 of the drawings there can be seen the two essential elements of the apparatus, comprising the external weight 1, in the cylindrical cavity 2 of which is located the ram 3, which can slide freely and is appropriately fitted with guiding rings 4.

At the upper portion of the external weight 1 is pro vided an oil pump 5 which in the present case is actuated by a hydraulic motor 6, the oil inlet and outlet conduits of which are indicated partially at 7 and 8. Between the above-mentioned pump and motor is mounted a shockabsorber device of a suitable type (not shown).

On the shaft of this motor 6 is keyed a crankshaft, the Wristpin 9 of which actuates the alternating translation movement of a double-piston 10 which is housed inside two coaxial cylinders 11 and 11'.

At the upper and lower ends of the hollow weight 1 are secured two fixed pistons 12 and 13, fitted with sealing rings, commonly arranged in alignment along the geometrical axis of the said weight and which pass respectively into two cylindrical chambers 14 and 15, which are fonmed in the ram 3 for that purpose.

From these two chambers 14 and 15 pass out two conduits 16 and 17 which open parallel to the above geometrical axis, on the upper cheek of the ram 3 and into which are inserted, through the intermediary of fluidtight packing linings 18, the lower extremities of two pipes 19 and 20, the heads of which are connected to the two coaxial cylinders 11-11 of the oil pump 5.

Under the lower end of the external weight '1 is fixed a cylindrical tail 21 which passes freely through the eye pierced in the centre of the check of the coupling bell 22. At the extremity of this tail 21 is rigidly fixed a retention plate 23 serving as a seating element for a series of Belleville washers 24 which are interposed between the plate and a retaining ring 25 fixed on the said tail 21.

The retention plate 23 is fixed at its opposite extremities to the rods 26 of the pistons of two hydraulic doubleacting jacks, the bodies 27 of which are rigidly fixed to the above-mentioned bell 22.

These cylinders are finally connected through a system of conduits shown very diagrammatically at 28 to a distributor 29 connected on the main conduit 30 which ensures the supply of oil under pressure.

The hydraulic system thus established permits, by a mere action on the distributor 29, the control at will of the simultaneous retractions or extensions of the two jacks considered, and consequently enables the degree of compression of the elastic washers 24 to be varied.

It will thus be readily understood that the flexibility of operation of such a system of coupling between the bell 22 and the external weight 1 provides the possibility of causing the tool, actuated under the control of the vibrohammer, to work either under percussion or under vibration at a controllable intensity.

In fact, the tool will work by percussion as long as the bell 22 does not come into contact with the retaining ring 25, and it will follow a vibratory operation when the said bell becomes seated on the said ring.

As has already been indicated above, the work of the tool may be facilitated by combining with the movements in an axial direction to which it is subjected, a rotary movement which may conveniently be impressed on the bell 22.

For this purpose, there is fixed on the body of the bell an external toothed ring 3-1, with which engages a driving pinion (not shown) driven in rotation by any adequate driving means desired.

In addition, the bell 22 is equipped with a gearbox having a step-up gear ratio of which only the four essential elements have been conventionally shown in the drawing, namely: a crown-wheel 32 with internal teeth, fixed to the said bell and engaging with a train of planetary pinions 33 driving an axial driven pinion 34 which carries a mandrel with automatic clamping, started at 35, and adapted to receive conventional drilling rods.

Thus, the apparatus will permit the execution of a bore in the interior of a tubular device directly fixed to the bell 22, by means of a tool which is gripped by the mandrel 35 and is set in rotation in a direction opposite to the gyratory movement of the said bell as soon as it meets with a certain resistance from the ground.

The conduit system ensuring the renewal of the oil in the circuit of the pump has not been shown in FIG. 1 in order to simplify and clarify the drawing, and this system forms the special subject of the diagram of FIG. 2, in which the constituent parts of this conduit system have been drawn in heavy lines, while the members to which the said parts are connected have been drawn in fine lines.

In FIG. 2, there is again found the hydraulic motor 6 and its outlet conduit 8 which terminates at the oil tank (not shown). At two points on this conduit 8 are connected two branch pipes 36 and 37 which open respectively into first one and then the other of the two cylinders 11 and 11' of the pump 5, and on the downstream side of which a throttling valve 38 having an adjustable flow-rate is arranged on the said conduit 8.

Opposite the two branch pipes 36 and 37, two pipes 39 and 40 start from the cylinders 11 and 11' referred to above, these latter pipes being connected to a third pipe 41 which is in turn connected at 42 to the main outlet conduit 8.

During the phase of operation in which the piston occupies a position such that it simultaneously uncovers the two orifices coupling the branch pipe 36 and the exhaust pipe 39 to the cylinder 11, the oil flowing out under pressure from the motor 6 through the channel of the conduit 8 encounters the throttling valve 38, which only permits the passage of a certain quantity of this oil, easily regulated by simple adjustment of the said valve 38.

Due to the effect of the resistance which this latter valve offers to the flow of oil, the remaining quantity of this flow is automatically compelled to follow directly the free path of the branch pipe 36 so as to pass into the cylinder 11, inside which its flow creates a turbulent movement which is extremely favourable to the complete renewal of the mass of liquid.

This mass progressively flows through the channel of the pipes 39 and 41 until it finally reaches the coupling point 42, the main conduit 8 terminating at the oil tank.

When the piston 10 is displaced towards the right until it simultaneously uncovers the orifices which connect the branch pipe 37 and the pipe 40 to the cylinder 11', the same cycle of renewal takes place, along the path of these latter, in the interior of the said cylinder 11', from which the fluid mass escapes, flowing through the circuit consisting of the elements 40, 41 and 8.

It will of course be understood that the invention is not limited to the details of the foregoing description, but comprises on the contrary all the alternative forms within the scope of those skilled in the art.

In this way, there may be substituted for the hydraulic motor 6 any other motors of absolutely any nature whatever, electric for example, the oil-renewal circuit in the pump 5 being then supplied from an appropriate auxiliary device.

Again in the same spirit, the motor-pump set 65 which, in accordance with the form of embodiment, detailed above, was rigidly fixed to the external striking mass 1, may be fixed to the ram 3, on condition that certain simple arrangements employing conventional mechanical means are adopted.

What I claim is:

1. An apparatus intended for carrying out various kinds of work, in particular drilling boreholes and pile-driving, which can impart at will longitudinal movements to a tool which is fitted to it, either of percussion or of vibration, said apparatus comprising a weight or ram adapted to be displaced with an alternating movement of translation inside a hollow weight, under the action of a fluid, means for injecting a fluid in order to effect the alternating move ment of said ram, means for fixing the tool, elastic means capable of being interposed at will between said tool and said ram, said apparatus being characterized in that the fluid pressure is applied in the interior of two axial cylindrical chambers or cylinders formed at the two extermities of the ram, inside which are engaged two fixed pistons secured opposite each other to the two ends of said hollow weight.

2. An apparatus as claimed in claim 1, characterized in that means are further provided for driving said tool in rotation.

3. An apparatus as claimed in claim 1 or claim 2, characterized in that the fluid under pressure is alternately distributed to one or the other of said cylinders by a doublepiston pump which pushes said fluid into conduits formed in the interior of said ram.

4. An apparatus as claimed in claim 3, characterized in that said double-piston pump is driven by a motor, especially a hydraulic motor.

5. An apparatus as claimed in claim 4, characterized in that said driving motor and said double-piston pump are conjointly arranged and rigidly fixed together at the top of said apparatus.

6. An apparatus as claimed in claim 1, characterized in that the coupling between said pump and said internal ram is effected by two fixed pipes issuing from said pump and rigidly secured to said external hollow weight through which they pass and which, sliding through sealing rings, pass into the interior of the channels or conduits pierced for that purpose in said ram, the fluid under pressure being led to said cylinders through said conduits.

7. An apparatus as claimed in claim 1, characterized in that said fluid circuit further comprises means for renewing said fluid.

8. An apparatus as claimed in claim 7, characterized in that the circuit of fluid under pressure comprises a throttling valve having a variable flow-rate, disposed on a conduit which directly joins the fluid admission pipe for the pump to the return or exhaust circuit of said fluid.

9. An apparatus as claimed in claim 8, characterized in that the fluid circulation system comprises two branch pipes connected upstream of the throttling valve and terminating at the two opposite cylinders of the pump, two exhaust pipes being further provided and coupled to the exhaust return circuit downstream of said throttling valve.

10. An apparatus as claimed in claim 1, characterized in that said fluid under pressure is oil.

11. An apparatus as claimed in claim 1, characterized in that it comprises at its lower portion a terminal toolcarrier element coupled to said ram by a device of adjustable elasticity.

12. An apparatus as claimed in claim 11, characterized in that said elastic device is constituted by a compression spring system arranged around a rod rigidly fixed to the striking weight and supported at one extremity on a seating base or plate adapted to slide freely on said rod, but fixed at an adjustable height to said terminal element, said spring system being locked at its other extremity by a ring fixed on the rod in the interior of said same terminal element and in abutment against the internal wall of said element.

13. An apparatus as claimed in claim 12. characterized in that said seating base or plate of said spring system is adjustable in height by the action of two double-acting hydraulic jacks, said jacks being supported at one extremity on said seating plate and at the other extremity on the internal face of said terminal element.

14. An apparatus as claimed in claim 11, characterized in that the terminal element to which said tool is attached is provided, at its external surface and along its periphery, with a toothed ring adapted for driving said element in rotation and, in its interior part, with a set of planetary gears, the axial pinion carrying a mandrel intended to receive a central drilling device and capable, if so required, of working inside the core of a tubular device directly fixed to said terminal element.

References Cited UNITED STATES PATENTS 904,528 1l/1908 Hamilton et a1 921l7 X 3,009,522 11/1961 Bedner 173-125 ERNEST R. PURSER, Primary Examiner US. Cl. X.R. 

